ABSTRACT
Greenhouse gas carbon dioxide (CO2) can be safely stored for thousands of years in deep underground geological formations. However, the design and modeling of CO2 injection and storage projects, knownasCO2 sequestration, poses significant technical issues in assessing their risks and consequences.The geological CO2 sequestration involves several trappingmechanisms, including the cap-rock trapping, residual, solubility, and mineral trapping. Therefore, complete simulation and modeling of CO2 sequestration requires the coupling of many processes, including compositional flow, thermal and geochemical effects, and transport of multiple reactive chemical species at multiple temporal and spatial scales. On the other hand, the reliability of these predictive simulations is adversely affected by poor conceptual models and by limitations in site characterization data. Moreover, these models require a large number of parameters to be determined. Thus the development of accurate, efficient and robust simulation tools supporting CO2 sequestration efforts represents a formidable modeling challenge. In this chapter, we present mathematical formulations of compositional model and reactive transport which involves three-phase flow modeling in porous media. In addition, we present ensemble-based methodologies for parameter estimation and uncertainty quantification of CO2 sequestration data.
